The newest line of camshafts from Comp Cams is the "Thumpr". This line of retro-fit hydraulic roller and hydraulic flat tappet cams is designed for use in engines that originally used a flat tappet cam. It will give a significant increase in horsepower over an identical flat tappet grind. The "Thumpr" uses lobe profiles and grind characteristics that produce an early valve opening, long exhaust duration, and a generous overlap to give the engine a powerful and hard hitting exhaust note and a rough idle without sacrificing power output or streetability.